Bell wore a beautiful, bright pink gown by J. Mendel, which featured red floral embroidery throughout.
She accessorized the frock with jewels from Lorraine Schwartz and Platinum Jewelry, and a matching pink box clutch.
Bell looked like a real-life princess on the carpet, sporting a chic, pulled-back updo and soft makeup.
ET spoke with the 37-year-old actress' makeup artist, Simone Siegl, who exclusively shared behind-the-secrets about getting Bell ready for the soirée.
Siegl says that when it comes to red carpet prep for awards show day, it's "all about teamwork." She collaborated with fashion stylist Nicole Chavez and hair guru Jenny Cho to create Bell's stunning look.
"My process of creating a look always begins after seeing both the dress and jewelry choices of Nicole Chavez," Siegl explains. "For the SAG Awards [ceremony], black gowns were chosen for all three looks, adding color brightness through the jewels, specifically platinum, because the natural white metal will bounce light and sparkle. For hair, [we decided] the styling would be up for most of the night, something I always like as it draws attention to Kristen’s great jawline."
She says she kept the beauty look simple by using two makeup brands. Siegl painted Bell's pout with Charlotte Tillbury Matte Revolution Lipstick in Pillow Talk, with mostly Neutrogena products on her face. As for why she went with a soft smokey eye, Siegl explains it's because "it is classic and strong."
"It also makes Kristen look so glamorous," she adds.
ET spoke with Bell last month, where she opened up about how she was feeling about the historic awards show gig. "I am so nervous, they've never done a host before," she confessed. "I just got a phone call, and I say yes to everything. I have a real problem saying no, so I was like, 'Sure!'"